The heart and pericardium.
I'm Thomas Gest and I'm professor of
anatomy at Central Michigan University College of Medicine.
In this presentation, we will define
the mediastinum and the location of the heart within it.
We will look at the vascular supply of the heart, and its external and internal features.
We will look at the conduction system of the heart.
The skeleton of the thorax is made up of the 12 ribs,
the costal cartilages, and the sternum, together with the thoracic vertebrae.
The first seven ribs are called the 'true ribs' because their costal cartilages contact the sternum directly.
The lowest five ribs are 'false ribs' because their costal cartilages don't contact the sternum directly.
Those of ribs 8, 9, and 10 contact the cartilage of rib 7,
while ribs 11 and 12 do not contact anything anteriorly, so they are called 'floating ribs'.
Note that the superior thoracic aperture is known as
the 'thoracic inlet' and also the 'thoracic outlet', just to confuse you.
The margin of the inferior thoracic aperture is the costal margin formed by the costal cartilages 7 through 10,
and the floating ribs 11 and 12.
Of course, the inferior thoracic aperture is closed off by the respiratory diaphragm.
The sternum (breastbone) has three parts: manubrium, body, and xiphoid process.
The manubrium has a jugular (or suprasternal) notch, between the sternoclavicular joints.
A very important landmark of the chest is the sternal angle, marking the
symphysis between the manubrium and the body of the sternum.
This is where the second costal cartilage connects to the sternum,
which is the highest cartilage and rib that you can palpate,
because the first rib is hidden by the clavicle.